Isaac b



(No Model.) I

I. B. KLEINERT.

DENTAL RUBBER. No. 583,307. Patented May 25,1897.

WITNESSES" lNVENTOR $4 1.; I v 1/5 m,

ATT RNEY UNITED STATES ATENT OFFICE.

ISAAC B. KLEINERT, OF NEIV YORK, N. Y.

DENTAL RUBBER.v

SPECIFICATION forming part of Letters Patent N 0. 583,307, dated May 25, 1897. Application filed February 23, 1897. Serial No. 624,582. (No model.)

To all whom it may concern:

Be it known that I, ISAAC B. KLEINERT, a citizen of the United States, and a resident of the city of New York, in the county and State of New York, have invented a new and useful Improvement in Dental Rubber, of which the following is a specification.

My invention is of a new and improved article of manufacture, consisting of a composite material formed of two kinds, qualities,

or characters of dental-rubber compounds,

substantially as described.

Heretofore in the preparation of foundation-plates as artificial-teeth supports it has been the custom of the dentists to compress a sheet of vulcanizable-rubber compound of one class, known as red dental rubber, into a matrix made from the wax impression of the mouth and then to compress upon it, with the fingers or hand-tools, a sheet of vulcanizable-rubber compound of a different class, known as pink dental rubber, and after setting the teeth subjecting the whole to a proper degree of heat in a vulcanizingoven until the rubber compounds were sufficiently vulcanized to be fit for the use intended. This method of forming the plate out of the two sheets was difficult and laborious, and it not unfrequently happened that the union of the sheets would not be so complete as to expel all of the air from between the adjacent surfaces, in which event, upon being subjected to heat in the vulcanizingoven, the air remaining so imprisoned would expand, separating the sheets in part or producing blisters, either of which happenings made the plate unfit for use, and it then represented merely so much wasted time and material. The necessity for using two sheets of different classes of vulcanizable-rubber compound arises from the fact that a compound that on being fully vulcanized will have the desired color for the exposed partsa color approximating to that of the natural gums of the mouth-will on being so vulcanized become too brittle or fragile to bear the strains that the foundation-plate must withstand when put to use, and hence a layer of such a material is superimposed rather as a matter of appearance than utility upon the substantial part of the foundation-plate, which consists of a vulcanizable-rubber compound that will on being fully vulcanized show a less desirable color, but will possess the necessary qualities of toughness and strength.

The production of a sheet of vulcanizablerubber com pound that shall be ready at hand for the dentists use as a single sheet, one side and the adjacent parts of which to a proper proportion of its thickness shall be com posed of avulcanizable-rubber compound of a class suitable for the exposed surface and the remainder of the sheet of a vulcanizable-rubber compound suitable for sustaining the working strain to which the finished plate will be subjected when in use, has long been regarded as a desirable and an important step in mechanical dentistry.

After diligent research and much experimenting I have invented and produced a composite sheet of vulcanizable-rubber compound that meets all of the requirements of the dentist in practicing this branch of his profession.

In practicing my invention I prepare a sheet of vulcanizable-rubber compound of substantially the same ingredients and in the same proportions as are used in the manufacture of the sheets now in use for the foundationlayer of the plate, andlprepare another sheet of a vulcanizable-rubber compound of substantially the same ingredients and in the same proportions as are used in themanufacture of the sheets now in use for the exposed layer of the plate. These sheets should bear to each other a proportionate thickness of from about three-fifths of the former to twofifths of the latter, but that proportion may be varied according to the toughness or fragility of the last-mentioned layer. The two sheets are then firmly rolled or pressed while hot into a single layer by pressure sufficient to secure perfect union between them and convert the two sheets into a single sheet, after which it is cut into convenient sizes and is then ready to be suitably packed and marketed for use.

The heating of the sheet can be well and conveniently done during the process of pressing by the use of heated presses or rolls, and the pressure should be sufficient to reduce the thickness of the finished sheet to about two-thirds or three-quarters of that of the two original sheets, so that each original sheet should be made a little thicker than as now generally made. also adds to the density of the material, and consequently a better plate can be formed from the sheet so constructed than is possible from the use of the two sheets separately manipulated in the matrix in manner described.

In the drawing I have illustrated one of my said sheets of dental rubber partly in perspective,whereon the portion composed of the tougher material is indicated by the letter a and that composed of the more fragile or surfacing material is indicated by the letter I). The exact relative proportionate thickness of these two classes of materials is not important, save onlythat the tougher of them must be of suficient bulk to serve its principal purpose of sustaining the strain that will be brought upon it through the medium of the teeth when the combined sheet shall have been formed into a dental plate,with the teeth added thereto, and put to use; but the combined sheets should be about one-twentieth of an inch in thickness, that being about the thickness ,of the completed plate as now generally made.

I am aware that it has been proposed to unite differently-colored sheets of rubber, as described in the United States Patent No. 448,795, and therefore do not claim this This heatin and ressin to make a bicycle-tire having the tread of harder material than the body thereof, but such tire material would be entirely unfitted for dental purposes.

I claim as new and desire to secure by Letters Patent- As an improved article of manufacture, a composite sheet of vulcanizahle rubber comprising two layers, one imitating the color of the gums and the other of tougher material, substantially as described.

In testimony that I claim the foregoing as my invention I have signed my name, in pres ence of two witnesses, this 18th day of February, 1897.

ISAAC l3. KLEINERT.

\Vitnesses:

JOHN W. SLATTERY, JAs. J. HANNAN. N 

